1. Field of the Invention
The present invention relates to reducing noise in computed tomography (CT) images during CT-fluoroscopy.
2. Discussion of the Background
CT-fluoroscopy involves continuous scanning of a slice or volume of a subject for monitoring in real time, such as monitoring interventions. If a regular dose of x-rays is used, the subject will be exposed to a large x-ray dose. If a lower dose is used, then image noise is increased. In CT, image noise is inversely proportional to the square root of the x-ray tube current. As the tube current is decreased to reduce dose, the image noise increases, resulting in poor image quality. One method used to reduce image noise is to average the image slices at the same location, but this produces blurring of the edges since there is bound to be movement of the subject, voluntary or involuntary, during the scan. For example, involuntary motion can be due to breathing or beating of the heart.